The present invention relates to optical instruments, in particular to magnification loupes, stereo-magnification loupes and magnification viewers, such as those worn by dentists and surgeons. The objective lens of the optical instrument is protected from mechanical and/or chemical damage.

A reading aid for magnifying text includes a first frame. The first frame comprises an annular wall that extends from a top to a bottom. The bottom is open. A first lens is positioned in the top. A second lens is adjustably coupled to an interior of the annular wall. The second lens is parallel planarly positioned relative to the first lens. A power module is coupled to the first frame. A plurality of lights is coupled to an upper end of the first frame. The lights are operationally coupled to the power module. The second lens is adjustably positionable relative to the first lens to obtain a magnification level required by a user. The lights are configured to illuminate a printed item positioned beneath the first frame such that the printed item is readable by the user.

A contactless visualization system is for a surgical microscope for eye surgery. The system includes an ophthalmic loupe positionable in front of a patient's eye and for supplying a real and vertically and laterally inverted image of an eye fundus of the patient's eye in an intermediate image plane observable by the surgical microscope. The ophthalmic loupe includes a first and a second lens element. In a state positioned in front of the patient's eye, the first lens element is closer to the patient's eye than the second lens element. A wall extends from the first to the second lens element. The wall has a free end in a form of a mount in which the second lens element is held. The mount includes at least one cutout in which an edge of the second lens element is exposed in order to give a surgeon operating space.

An optical magnifying combination lens, a head-mounted optical display system and a virtual reality display device are provided, wherein the optical magnifying combination lens is for utilization in a head-mounted virtual reality display device, comprising: a central area (A) and a peripheral area (B), wherein the central area (A) is a convex lens or a combination convex lens, and the peripheral area (B) is a focusing thin optical element; the central area (A) corresponds to main visual field imaging, and the peripheral area (B) corresponds to peripheral visual field imaging. The optical magnifying combination lens guarantees center image quality and enlarges edge view of human eyes, so as to enhance user immersion feelings.

An optical magnifying combination lens, head-mounted display optical system and virtual reality display device. The optical magnifying combination lens (2) is used in a head-mounted virtual reality display device and includes a main lens (21) and a secondary lens (22), the main lens (21) including a central area (A) and an peripheral area (B), wherein the central area (A) comprises a convex lens or a combined convex lens, and the peripheral area (B) is a focusing thin optical element. The secondary lens (22) is a focusing thin optical element formed with a hollowed-out region. The main lens (21) and the secondary lens (22) are stacked together, and the hollowed-out region of the secondary lens (22) closely fits with a convex portion of the central area (A) of the main lens (21). The display device using the optical magnifying combination lens (2) ensures central image quality, and expands a peripheral field of view of a human eye, thus increasing user immersion.

An optical system includes, in order from the pupil plane side to the display plane side, a first reflective polarizing plate, a first lens having a convex surface on the pupil plane side, a half mirror, a second lens having a convex surface on the display plane side, a second reflective polarizing plate, a first wavelength plate, and a second wavelength plate. The optical system satisfies:

[00001]$\begin{array}{cc}14<r1/T1<250& \left(1\right)\end{array}$$\begin{array}{cc}0.7<\left(D2/f2\right)100<5.& \left(2\right)\end{array}$

where r1 is the paraxial radius of curvature of a surface of the first lens on the pupil plane side, T1 is the distance on an optical axis from a surface of the first lens on the display plane side to a surface of the second lens on the pupil plane side, D2 is the thickness of the second lens L2 on the optical axis, and f2 is the focal length of the second lens.

Apparatus, including a housing that is configured to be mounted in proximity to a human eye. The apparatus further includes optics that is retained by the housing and that is configured to focus optical radiation from a scene to an image viewable by the human eye. The apparatus also includes a tunable wavelength filter that is retained by the housing and that is configured to sequentially filter the optical radiation from the scene by a first wavelength and by a second wavelength different from the first wavelength.

Lens barrel includes: a rotating barrel which holds a first optical system and includes an adjustment member that can protrude from an inner circumferential surface; and a fixed barrel which holds a second optical system and includes a helical groove with which the adjustment member engages on an outer circumferential surface. The adjustment member can be located in a first or a second position with respect to the helical groove. Part of the adjustment member is in the helical groove in any of the first position and the second position. When in the first position, the adjustment member can slide along the helical groove, so the rotating barrel helically rotates relative to the fixed barrel, and when in the second position, the adjustment member is in contact with the helical groove, to prevent rotation of the rotating barrel with respect to the fixed barrel.

A magnifying container apparatus including a generally cylindrical member and one or more magnifying lenses is provided for magnifying, viewing, and carrying items. A magnifying lens is detachably connected to the lower end of the cylindrical member to close the lower end. The magnifying lens magnifies the items present below the magnifying lens. The cylindrical member accommodates and carries the items within a space defined by a generally cylindrical wall and between an open upper end and the closed lower end of the cylindrical member. The magnifying container apparatus further includes a threaded rod, a threaded wheel, and a generally cylindrical sieve member. The sieve member drains a predetermined amount of an extraneous element from the magnifying container apparatus, when the threaded rod, in communication with the threaded wheel, traverses the magnifying lens from the lower end of the cylindrical member toward a lower end of the sieve member.

An ocular optical system comprising at least five lens elements, and including, in order from a display surface side to an exit side, a first lens unit having negative optical power, a second lens unit having positive optical power, and a third lens unit having positive optical power, wherein the second lens unit moves along an optical axis for adjustment of diopter scale, and a finder optical system comprising a display device having a display surface on which an image is displayed, and the above-mentioned ocular optical system.